What I am looking for: The ability to run seperate leagues at one time. Each user has their own login and can create/administer their own leagues. Users should be able to invite others to join their league. This would be similar to a pick'em script however I want to make it so people could only select a predetermined number of selections. Admin should be able to input game results and have the script calculate each leagues stats w/l/points automatically. Should also have the ability to accept payments for people to create their own leagues. Any suggestions?
Have you considered starting with an open source option such as Joomla! (http://www.joomla.org)? If you take this route, there are plenty of free/cheap extensions (http://extensions.joomla.org) that may accomplish what you are needing.